Is s/pdif better than TRS or XLR?

PB26 · November 24, 2014 at 11:43 PM

I've been trying to read up as much as possible on different ways of recording the lovely tones from my toaster, and I keep seeing people talking about s/pdif. Is this just for reamping (which I don't want to do) or is it possible to record the full rig by just hooking up the Kemper s/pdif out to the s/pdif input on the interface? Are there any advantages?

I plan on picking up a new interface in the $250-$300 range with some store credit I haven't used up, and I wonder if I should consider the absence of a s/pdif outlet as a deal-breaker.

chamelious · November 25, 2014 at 12:51 PM

Yes you can record the Master Stereo signal via SPDIF, and in doing so you avoid the AD/DA converters of your soundcard/workstation. This is avoiding a step which can cause a loss of quality (some people spend a LOT on converters) but for the average user, the quality difference probably won't be noticeable.

PB26 · November 25, 2014 at 2:01 PM

Thanks, I'll give it a try.

Ingolf · November 25, 2014 at 4:53 PM

Practically speaking the difference between SPDIF and going analog should be marginal but like Chamelious said it's one A/D D/A conversion less.

Michael_dk · November 25, 2014 at 6:00 PM

Yeah. For me, I would have NO problem using the TRS inputs on my focusrite safari pro interface, which is a decent prosumer quality, I guess. I always use SPDIF, but that's only due to workflow. I recommend getting an interface with spdif for this reason, if you think you're gonna do ANY reamping. Also just for testing out tones without playing at the same time

MIND YOU, you can setup analogue connections to work for this also. You can just set it up with spdif easier, i think, and maintain the right gain staging.

PB26 · November 25, 2014 at 6:40 PM

Cool, thanks. I think I'll get the Focusrite Scarlett 6i6 USB. The Presonus I was looking at has no s/pdif connector.

skoczy · November 25, 2014 at 10:42 PM

Quote from PB26

Cool, thanks. I think I'll get the Focusrite Scarlett 6i6 USB. The Presonus I was looking at has no s/pdif connector.

I am also interested in Focusrite Scarlett 6i6 USB since this is "lowest" Scarlett with SPDIF. I've been Focusrite user for few years and I find their interfaces good in terrms of stability. Using SPDIF saves you 2 inputs and lets you omit 2 stages of conversion. Once in Kemper from digital singal into analog on Kemper's output and secondly on the input on interface when analog signal has to be converted into digital. And reamping is easier with SPDIF.

mDan · November 25, 2014 at 11:33 PM

Especially when you are reamping SPDIF is extremely convenient!

PB26 · November 25, 2014 at 11:44 PM

To set it up so that the full processed signal comes out of the Kemper, is it just one cable -- Kemper s/pdif out to interface s/pdif in?

Then for the Kemper setting in the "Output" section, is it just "Master Stereo"? EDIT: This question already answered by chamelious, above!

Finally, I've read stuff about the "clock" and "master" and "slave." No clue what this is. Is it a setting done on the Kemper or the interface? .

creative360 · November 26, 2014 at 2:31 AM

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PB26 · November 26, 2014 at 4:54 AM

Quote from creative360

Your sound card setup interface should offer you several clock options, SPDIF being one of them.

Kemper SPIDF out offers some cool options, and also demands certain compromises. Conventional wisdom says it's the way to go, saving a round of A/D conversion and it's what I've been doing in my home studio. But for the past couple months I've been working on an album project with a composer who has been recording me via the KPA's XLR outs stereo direct at 48k, and it has me rethinking my process. The results, from a purely audiophile perspective, are stunning.

Curious, what device are you plugging the XLRs into, and from there is it into the computer?

CadaverHK · November 26, 2014 at 6:22 AM

I have the 6i6, and bought it because of the SPDIF I/O.

I can hear there is a noticeable difference between SPDIF and line signal. SPDIF sounds more crisp and has a clearer top end, where as the line signal sounds warmer. Also, with SPDIF I don't need to worry about the signal level into the DAW, I leave it at 0db and it never clips, no matter how hard I pick. I set the SPDIF output to DI and Stack, and record both tracks at 44.1kHz in Logic.

I leave the line and XLR outputs for live use only.

PB26 · November 26, 2014 at 6:25 AM

Quote from CadaverHK

I have the 6i6, and bought it because of the SPDIF I/O.

I can hear there is a noticeable difference between SPDIF and line signal. SPDIF sounds more crisp and has a clearer top end, where as the line signal sounds warmer. Also, with SPDIF I don't need to worry about the signal level into the DAW, I leave it at 0db and it never clips, no matter how hard I pick. I set the SPDIF output to DI and Stack, and record both tracks at 44.1kHz in Logic.

I leave the line and XLR outputs for live use only.

Awesome, can't wait to get my hands on one of those 6i6's.

creative360 · November 26, 2014 at 7:08 AM

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Michael_dk · November 26, 2014 at 7:10 AM

I would guess that any audible difference between spdif and TRS/XLR route is due to the analogue signal chain BEFORE the converters in the audio interface (the scarlett)

nightlight · November 26, 2014 at 10:53 AM

Quote from Michael_dk

I would guess that any audible difference between spdif and TRS/XLR route is due to the analogue signal chain BEFORE the converters in the audio interface (the scarlett)

My guess is that it would be a combination of the cables being used and the A/D conversion when the signal goes back into your interface in the digital domain.

viabcroce · November 27, 2014 at 3:43 AM

Conversions are not a neutral process, and converters do have a sound. It's not necessarily so, but no surprise that a couple of further conversions change the sound.

Michael_dk · November 27, 2014 at 7:22 AM

I still think most of the sound of a converter is in the analogue circuit of the converter until the signal hits the chip Although I've heard that for instruments with very strong transients (i.e. drums), the power supply is the limiting factor - how quick it reacts to the increase in voltage necessary - or something

viabcroce · November 27, 2014 at 4:06 PM

There's a whole science about converters

Let's not forget that they use analog currents and tensions to express "high" and "low" values. Also, they need filters, they operate in real time (so velocity is a factor), they have jitter... lots of elements which create a complex microcosm not easy or trivial to analize or describe. People have written whole books or articles on the matter.